Tokyo, June 5:

Japan’s best-known fund manager, Yoshiaki Murakami, was arrested for alleged insider trading in a case that is drawing intense attention in a nation where aggressive investment funds are still relatively rare, Japanese TV networks reported.

Murakami, president of MAC Asset Management known as Murakami Fund, acknowledged on Monday he had engaged in insider trading. Prosecutors arrested Murakami on Monday afternoon after questioning him, public broadcaster NHK and other media reports said. Investigators also raided the Tokyo headquarters of MAC Asset Management and other related properties, the reports said.

An official at the Tokyo District Prosecutors’ office said he wasn’t aware of Murakami’s arrest. Attempts to contact MAC Management officials were unsuccessful.

Tokyo prosecutors and the Securities and Exchange Surveillance Commission suspect that his Murakami Fund bought a large quantity of shares in Nippon Broadcasting System Inc last year based on advanced knowledge that Internet firm Livedoor Co would make a takeover bid for it.

Murakami denied in a nationally televised news conference Monday that he intended to commit a crime when he bought a large number of Nippon Broadcasting System Inc. shares with advance knowledge that Internet startup Livedoor Co would make a takeover bid for the

radio network.

He said he chanced upon that information and was not fully aware that his actions may have constituted insider trading.

“I didn’t intend to commit a crime,” Murakami said. “I made a mistake.” Livedoor executives, including its flamboyant former president, Takafumi Horie, are embroiled in a separate criminal case, centered on falsifying its own earnings reports and those of a subsidiary. Horie was arrested earlier this year on charges of violating securities exchange regulations.

Murakami, a 46-year-old former government bureaucrat, rose to fame as an outspoken proponent of investor rights and free markets. But he was widely viewed with suspicion by many among the old-guard business establishment as just being out for money and representing dubious foreign investors, and not interested in proper Japanese management practices.

Murakami said Monday he had signed a document with Tokyo prosecutors admitting wrongdoing, and he expected to be charged. He also said he was stepping down as fund manager.